1,5-NAPHTHALENE DIISOCYANATE Data were last reviewed in IARC (1979) and the compound was classified in IARC Monographs Supplement 7 (1987). 1. Exposure Data 1.1 Chemical and physical data 1.1.1 Nomenclature Chem. Abstr. Serv. Reg. No.: 3173-72-6 Chem. Abstr. Name: 1,5-Diisocyanatonaphthalene IUPAC Systematic Name: Isocyanic acid, 1,5-naphthylene ester 1.1.2 Structural and molecular formulae and relative molecular mass NCO O C N C12H6N2O2 Relative molecular mass: 210.20 1.1.3 Chemical and physical properties of the pure substance (a) Description: White to light yellow, crystalline solid (Lewis, 1993) (b) Boiling-point: 183°C (Ulrich, 1989) (c) Melting-point: 130–132°C (Ulrich, 1989) (d) Conversion factor: mg/m3 = 8.60 × ppm 1.2 Production and use 1,5-Naphthalene diisocyanate is reported to be produced by two companies in Japan and one in Germany (Chemical Information Services, 1995). 1.3 Occurrence No data were available to the Working Group. –1515– 1516 IARC MONOGRAPHS VOLUME 71 1.4 Regulations and guidelines The American Conference of Governmental Industrial Hygienists (ACGIH) (1997) has not proposed any occupational exposure limit for 1,5-naphthalene diisocyanate in workplace air. Values ranging from 0.02 to 0.095 mg/m3 for a time-weighted average and from 0.01 to 0.07 mg/m3 for short-term exposure limits have been used as standards or guidelines in several countries (International Labour Office, 1991; United States National Library of Medicine, 1997). No international guideline for 1,5-naphthalene diisocyanate in drinking-water has been established (WHO, 1993). 2. Studies of Cancer in Humans No data were available to the Working Group. 3. Studies of Cancer in Experimental Animals No data were available to the Working Group. 4. Other Data Relevant to an Evaluation of Carcinogenicity and its Mechanisms 4.1 Absorption, distribution, metabolism and excretion No data were available to the Working Group. 4.2 Toxic effects 4.2.1 Humans Acute damage to the respiratory tract as well as conjunctivitis were observed in workers employed in the production of polyurethane rubber, in which 1,5-naphthalene di- isocyanate was the basic chemical. An association has been reported between bronchitis and exposure to 1,5-naphthalene diisocyanate (IARC, 1979). The irritative effects of 1,5-naphthalene diisocyanate were confirmed in a further study of rubber production workers, in which exposure over the range of 0.002–0.007 mg/m3 was associated with increased frequency of eye irritation, cough and exertion dyspnoea. Also, an increase in the closing volume, especially among the older workers, was observed, suggesting airway irritation (Alexandersson et al., 1986) 4.2.2 Experimental systems No data were available to the Working Group. 1,5-NAPHTHALENE DIISOCYANATE 1517 4.3 Reproductive and developmental effects No data were available to the Working Group. 4.4 Genetic and related effects No data were available to the Working Group. 5. Evaluation No epidemiological data relevant to the carcinogenicity of 1,5-naphthalene diiso- cyanate were available. No experimental data relevant to the carcinogenicity of 1,5-naphthalene diisocyanate were available. Overall evaluation 1,5-Naphthalene diisocyanate is not classifiable as to its carcinogenicity to humans (Group 3). 6. References Alexandersson, R., Gustafsson, P., Hedenstierna, G. & Rosen, G. (1986) Exposure to naphthalene- diisocyanate in a rubber plant: symptoms and lung function. Arch. environ. Health, 41, 85–89 American Conference of Governmental Industrial Hygienists (1997) 1997 TLVs® and BEIs®, Cincinnati, OH, pp. 1013–1014 Chemical Information Services (1995) Directory of World Chemical Producers—1995–1996, Standard Edition, Dallas, TX, p. 278 IARC (1979) IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans, Vol. 19, Some Monomers, Plastics, Synthetic Elastomers, and Acrolein, Lyon, pp. 303–340 IARC (1987) IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Supple- ment 7, Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, Lyon, p. 67 International Labour Office (1991) Occupational Exposure Limits for Airborne Toxic Substances, 3rd Ed. (Occupational Safety and Health Series No. 37), Geneva, pp. 286–287 Lewis, R.J., Jr (1993) Hawley’s Condensed Chemical Dictionary, 12th Ed., New York, Van Nos- trand Reinhold, pp. 805–806 Ulrich, H., (1989) Acrylic acid and derivatives. In: Gerhartz, W. & Yamamoto, Y.S., eds., Ullmann’s Encyclopedia of Industrial Chemistry, 5th rev. Ed., Vol. A 14, VCH Publishers, pp. 611–625 United States National Library of Medicine (1997) Registry of Toxic Effects of Chemical Subs- tances (RTECS) Database, Bethesda, MD [Record No. 95536] WHO (1993) Guidelines for Drinking Water Quality, 2nd Ed., Vol. 1, Recommendations, Geneva.